Polyamide is known to have excellent mechanical properties combined with satisfactory heat resistance and abrasion resistance. Taking full advantage of these performance properties, it is utilized as electrical insulating materials, various molding materials, coating materials, impregnating materials, and the like in a wide application, such as domestic and industrial equipments or devices, electronic industrial parts, automobile parts, gears, etc.
Inspite of the excellent characteristics, polyamide, particularly aromatic polyamide, has extremely poor processability. Namely, the aromatic polyamide is hardly melted; or, if melted, requires a very high temperature for melting; or organic solvents in which it is soluble are limited to a very narrow range. As a result, great difficulties arise in processing polyamide.
In order to eliminate this disadvantage, it has been proposed to polycondensate an aromatic etherdiamine and an aromatic dicarboxylic acid or a reactive derivative thereof to produce an aromatic polyetheramide polymer having excellent processability, as disclosed in U.S. Pat. No. 4,278,786.
The above-described aromatic polyetheramide polymer is characterized not only by its excellent processability but by excellent heat resistance. However, since this polymer is thermoplastic, though excellent in heat resistance, it undergoes melting and deformation at temperatures over the range of allowable high temperature use.